1,3-Dipolar cycloaddition of diaryldiazomethanes across N-ethoxy-carbonyl-N-(2,2,2-trichloroethylidene)amine and reactivity of the resulting 2-azabutadienes towards thiolates and cyclic amides

1,3-dipolar cycloaddition of diaryldiazomethanes Ar2C=N-2 across Cl3C-CH=N-CO2Et 1 yields Delta(3)-1,2,4-triazolines 2. Thermolysis of 2 leads, via transient azomethine ylides 3, to diaryldichloroazabutadienes [Ar(Ar')C=N CH=CCl2] 4. Treatment of 4a (Ar = Ar' = C6H5) and 4c (Ar = Ar' = p-ClC6H4) with NaSR in DMF yields 2-azabutadienes [Ar2C=N-C(H)= C(SR)(2)] 5. In contrast, nucleophilic attack of NaStBu on 4 affords azadienic dithioethers [Ar2C= N-C((SBu)-Bu-t)=C(H)((SBu)-Bu-t)I (7a Ar = C6H5; 7b Ar' = p-ClC6H4). The reaction of 4a with NaSEt conducted in neat EtSH produces [Ph2C=N C(H)(SEt) CCI2H] 8, which after dehydrochloration by NaOMe and subsequent addition of NaSEt is converted to [Ph2C=N C(SEt)= C(H)(SEt)] 7c. Upon the reaction of 4c with NaS'Pr, the intermediate dithioether [(p-ClC6H4)(2)C=N-CH=C((SPr)-Pr-i)2] 5k is converted to tetrakisthioether [(p-(PrSC6H4)-Pr-i)(2)C=N-CH= C((SPr)-Pr-i)(2)] 6. Treatment of 4a with the sodium salt of piperidine leads to EPh2C=N-CH= C(NC5H10)(2)]10. The coordination of 6 on CuBr affords the macrocyclic dinuclear Cu(I) complex 11. The crystal structures of 5i, 7a,b, 10 and 11 have been determined by X-ray diffraction. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license.